remarkable for its widely different rates between various ethnic groups. The baby's sleeping position and whether or not the mother smokes appear to have a direct bearing on those rates.

16 World Health • 49th Yeor, No. 2, Morch-Aprill996

Sudden infant death syndrome

Hazel Brooke

Baby sleeps an its back and with its mother. The way Asian Families tend their infants may have a bearing on the low rate of Sudden Infant Death Syndrome.

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In the First Book of Kings in the Old Testament, written about 500 BC, we read: "And this woman's child died in the night; because she overlaid it". For many centuries overlying by the mother (causing suffocation) was accepted as the cause of sudden unexpected infant deaths. It was not until the late 18th century that doctors began to explore other possible causes for such deaths, beginning with the hypothesis that these infants suffered from an en- larged thymus, leading to "internal suffocation". This was widely ac- cepted throughout the 19th century and indeed into the 1930s, when it became discredited.

In 1969, a definition of the term Sudden Infant Death Syndrome (SIDS) was agreed upon at an inter- national conference in the USA:

Commonly known as "cot deaths", the Sudden Infant Death Syndrome is

remarkable for its widely different rates between various ethnic groups. The baby's sleeping position and whether or not the mother smokes appear to have a direct bearing on those rates.

"The sudden death of any infant or young child, which is unexpected by history and in which a thorough postmortem examination fails to demonstrate an adequate cause for death".

The second half of the 20th cen- tury has seen many hypotheses proposed about the cause of these deaths. Millions of research dollars have been spent on efforts to identify the mechanism of death, and these efforts are continuing. The SIDS rate is now less than 1 per 1000 live births in most Western cultures. At the same time, medical science has been taking increasing interest in the differences that exist in the SIDS rates between various ethnic groups.

For example, studies have shown a low rate among Asian families, even if they are immigrants living in a Western society. Most researchers now feel that there are useful lessons to be learnt from different cultural practices in relation to child care.

Let us look at three widely accepted recommendations on reducing the risks of SIDS.

World Health • 49th Year, No. 2, March-Aprill996

1. Place your baby on its back to sleep.

Many studies have indicated a strong association between prone (front) sleeping and the occurrence of SIDS.

The practice of placing babies face downwards to sleep became popular in many Western countries in the 1970s and 1980s- a period marked by high SIDS figures. Prone sleep- ing is not favoured in Asian families, even those resident in Western soci- eties. Evidence from Hong Kong, where there are virtually no cases of SIDS, confirms this avoidance of prone sleeping. In countries where, over the past few years, a strong message has been conveyed to par- ents to avoid the prone sleeping position, there has been a marked reduction - in some cases of 60% - in the number of SIDS cases. This would strongly suggest that the Western practice of placing infants prone for sleep was actually harmful.

Smoking is harmful for the foetus. When the habit continues after the birth, the infant will be put at increased risk of Sudden Infant Death Syndrome.

2. Avoid smoking during pregnancy and around the baby during the first year of life.

Smoking, particularly among moth- ers, has emerged as a major risk factor for SIDS. Studies have shown that maternal cigarette smoking increases the risk of SIDS for a baby as much as sevenfold, with an even greater risk if the father smokes too.

In New Zealand, where a forceful campaign to reduce the risks of SIDS has been promoted since 1990, there has been a striking drop in the inci- dence of SIDS among non-Maori infants, but a far less marked reduc- tion among Maoris, whose infants are now four times as likely to be SIDS victims as non-Maori infants.

Researchers in that country are convinced that one of the reasons for this difference is that Maori women are twice as likely to smoke as non- Maori women. Smoking was intro- duced relatively recently in Maori society but has become a cultural norm. Conversely, smoking is un- common among Asian women, whose infants seem to be at very low risk of SIDS.

3. Avoid overwrapping your baby.

Studies have indicated that babies may be at increased risk of SIDS if they are too warm. A study of Welsh and Bangladeshi families in Cardiff, Wales, published in 1993, demon- strated that the Asian mothers were much more concerned about the danger of their infant overheating, and this was one of the explanations given for the practice of shaving babies' heads. Welsh mothers, on the other hand, were anxious to keep their infants warm.

Is stimulation desirable?

Over the past three years, consider- able interest has also focused on the possibility that stimulation may play a role in reducing the risk of SIDS.

Asian families, with their low SIDS incidence, often live in an extended- family situation, with aunts, uncles, cousins and grandparents forming part of the household. The baby is kept in the heart of the family during the day, subject to the noise and bustle and accustomed to a busy social and tactile environment.

Western babies are much more likely to be placed "somewhere quiet" for sleep periods; the suggestion has been made that this lack of both supervision and stimulation may not be advantageous.

Be careful not to leave your baby alone for too long.

17

At night the Asian infant sleeps either in bed with the mother or in a cot next to her. The fact that this practice is associated with a low incidence of SIDS has led some researchers to think that bed-sharing may be desirable for all infants.

However, research from New Zealand has indicated a significantly increased risk of SIDS for infants sharing a bed with a mother who smokes. Maori mothers are twice as likely as non-Maoris to both smoke and bed-share.

Bed-sharing is a traditional infant care practice for the Maori, while smoking is an introduced practice.

Educators in New Zealand are there- fore trying to discourage smoking, while encouraging the treasured tradition of bed-sharing. The low incidence of SIDS among bed-shar- ing Asian infants may reflect the fact that few Asian mothers smoke.

Cultural differences may well suggest valid ways of reducing the risks of SIDS, but it is important to see these differences as interdepen- dent parts of rich and varied cultures, rather than in isolation. In addition, we may have to face, in all our cul- tures, a rise in SIDS rates caused by the use of illegal substances. •

Mrs Hazel Brooke is Chairman of SIDS International. Her address is Scottish Cot Death Trust, Royal Hospital for Sick Children, Yorkhi/1, Glasgow G3 8Sj, Scotland.